Inspiratory Resistance Delays the Reporting of Symptoms with Central Hypovolemia: Association with Cerebral Blood Flow

Abstract

We tested the hypothesis that breathing through an inspiratory threshold device (ITD) during progressive central hypovolemia would protect cerebral perfusion and attenuate the reporting of presyncopal symptoms. Eight human subjects were exposed to lower-body negative pressure (LBNP) until the presence of symptoms while breathing through either an active ITD (-7 cmH2O impedance) or a sham ITD (0 cmH2O). Cerebral blood flow velocity (CBFV) was measured continuously via transcranial Doppler and analyzed in both time and frequency domains. Subjects were asked to report any subjective presyncopal symptoms (e.g., dizziness, nausea) at the conclusion of each LBNP.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2007
Accession Number
ADA629270

Entities

People

  • Caroline A Rickards
  • Kathy L. Ryan
  • Keith G. Lurie
  • Victor A Convertino
  • William H. Cooke

Organizations

  • United States Army Institute of Surgical Research

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Arteries
  • Blood
  • Blood Flow
  • Blood Volume
  • Cardiovascular Diseases
  • Cardiovascular Physiological Phenomena
  • Cardiovascular System
  • Data Analysis
  • Diseases And Disorders
  • Frequency
  • Frequency Domain
  • Hemorrhage
  • Hemorrhagic Shock
  • Hypotension
  • Respiratory Physiological Phenomena
  • Transfer Functions
  • Vascular Diseases

Fields of Study

  • Medicine
  • Psychology

Readers

  • Cardiovascular Physiology